I agree with you with the power cutting off thing. My unit shuts off after 36 hours normally and I have to go to the trunk where my battery is. However, other cars, if you have an A4, the battery is near the steering wheel so you can just mount your powerbox inside your car in the cockpit.

As for parking, I have yet to have any problems, you can always set the sensitivity to highest in the options in order to catch every detail. I also recommend getting a 32gb micro sd card to ensure the cam will capture the most it can prior to you going to your car and saving the videos that are important.

I will investigate this parking mode further to see if I have the same issues as you.

I have 32GB card and the sensitivity settings are on the max. But it has nothing to do with recording continuously. Let me know if you find out anything.

Also, the DR400G-HD has some overheating issues - it gets burning hot even in parking mode.